Is it possible to lose weight while pregnant

In a healthy way ? I’m 5”6 and 260lbs. My boyfriend and I just decided to start working on our weight.. now I’m finding out I’m pregnant. I’m terrified I’ll put on so much weight I’ll be 300 lbs by the end of this all.

I don’t see my doctor until March 20th so I can’t voice my concerns.. just curious if it’s possible to walk a lot, snack on fruits and vegetables and eat healthy while pregnant to keep my weight down??